Mentally ill chemical abusers (MICAs) are characterized by poorer adaptive functioning, and less consistent involvement in treatment and social services when compared to single-diagnosis disorders. The proposed research will extend current knowledge about the psychosocial adjustment of MICA patients by using (1) a multivariate approach; (2) standardized measures of known reliability and validity; and (3) a prospective, longitudinal design. One hundred and twenty male and female psychiatric patients will serve as subjects. Four groups (n = 30) will be created by crossing psychiatric diagnosis (schizophrenia, mood disorder) and substance abuse (present, absent). Cross-sectional comparisons can be made on variables such as substance use history and current patterns, psychiatric symptom levels, social adjustment, coping skills, and neuropsychological capacity. A follow-up assessment will be conducted six months later, during which measures of treatment utilization and of psychiatric and substance abuse status will be obtained. Thus, baseline variables can be used to predict subsequent psychosocial adjustment. The specific aims of the proposed research are: (1) to describe the four subject groups in terms of psychiatric presentation, substance use, and social functioning; (2) to characterize the nature and extent of neuropsychological impairment in MICA patients, and to determine the relationship between neuropsychological impairment and coping skills; (3)to evaluate the clinical course of comorbid mental illness and sub- stance abuse; and (4) to identify the variables associated with short-term psychosocial adjustment in MICA patients. The long-term goal of the proposed research is to enhance our understanding of MICA patients so that we can design new treatments, and modify existing protocols, to meet the unique and complex needs of this prevalent patient population.